Measurement of the branching ratios b → e ν X, μ ν X, τ ν X and ν X

The inclusive semileptonic branching ratios b → e ν X, μ ν X, τ ν X and ν X have been measured at LEP with the L3 detector. The analysis is based on 2-jet hadronic Z decays obtained in the data collected between 1991 and 1992. Three separate event samples are analysed, containing electrons, muons and large missing energy (neutrinos), respectively. From the electron sample, we measure Br(b → e ν X) = (10.89±0.20±0.51)% and, from the muon sample, …